es-dev-server/dist/utils/is-modern-browser.js

Development server for modern web apps

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.isModernBrowser = void 0;
const browserslist_useragent_1 = require("browserslist-useragent");
const utils_1 = require("./utils");
/**
 * We skip babel compilation for the latest versions of the major browsers.
 *
 * Chrome, Edge and Firefox: releases frequently so we take the latest 2
 *
 * Safari/iOS Safari: releases infrequently so we take the latest 1
 *
 * Chromium based browsers like Brave, Yandex and Opera: unsure how
 *   often they release, so not what strategy to pick. Ideally we have a
 *   way to map from browser version to chromium version.
 */
const modernBrowsers = [
    'last 2 Chrome major versions',
    'unreleased Chrome versions',
    'last 2 ChromeAndroid major versions',
    'unreleased ChromeAndroid versions',
    'last 2 Edge major versions',
    'unreleased Edge versions',
    'last 2 Firefox major versions',
    'unreleased Firefox versions',
    'last 2 FirefoxAndroid major versions',
    'unreleased FirefoxAndroid versions',
    'last 1 Safari versions',
    'last 1 iOS versions',
];
/**
 * Usually browsers implement new features before they become browser standards.
 * Sometimes not all browsrs have implemented them before they become a standard.
 *
 * If these are features with a significant developer or end-user benefit, we make
 * exceptions for certain browser versions to lose the speed benefit.
 *
 * Unimplemented features currently being tracked:
 * - Optional chaining
 * - Nullish coalescing
 *
 * This list should be curated, when the latest 1 or 2 of the major browsers have
 * implemented these features, we can clear the override list.
 */
const unimplementedFeatures = [
    // <= does properly match, so we list the latest 2 versions which doesn't support it,
    // the rest will be filtered by the other check
    'Chrome 78',
    'Chrome 79',
    'ChromeAndroid 78',
    'ChromeAndroid 79',
    // (edge 78 does not exist)
    'Edge 79',
    'Firefox 72',
    'Firefox 73',
    'FirefoxAndroid 72',
    'FirefoxAndroid 73',
    'Safari 12',
    'Safari 12.1',
    'Safari 13',
    'iOS 12',
    'iOS 12.1',
    'iOS 13',
];
function isModernBrowser(userAgent) {
    if (browserslist_useragent_1.matchesUA(userAgent, { browsers: unimplementedFeatures })) {
        utils_1.logDebug(`Forcing compatibility mode on user agent ${userAgent} because it does not` +
            ' implement all standard stage 4 features.');
        return false;
    }
    return browserslist_useragent_1.matchesUA(userAgent, {
        browsers: modernBrowsers,
        allowHigherVersions: true,
    });
}
exports.isModernBrowser = isModernBrowser;
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